Lower East Side residents are suing to save a decades-old garden they cultivated from a vacant lot after appeals to politicians and celebrities like “Sex in the City” star Cynthia Nixon failed to stop a developer’s plan to bulldoze the green space.

“This has been our community garden for the last 30 years,” said Kate Temple-West, head of the Children’s Magical Garden at the corner of Norfolk and Stanton streets. “Every tree, every plant, every bush means a lot to the community.”

The activists weeded out vermin, used needles and discarded metal from the vacant lot in 1985– transforming the lot into an “urban oasis” that hosted local schoolchildren for nature and art sessions, according to the Manhattan civil lawsuit filed Monday.

The activists say pleas to property owner Serge Hoyda to preserve the space were ignored.

He sold the lot to a Yonkers real estate company called the Horizon Group for $3.35 million in January.

Benjamin Burry, attorney for the garden, is asking the court to enforce a centuries-old legal doctrine called adverse possession that would give the activists ownership over the parcel because they’ve occupied it for 10 consecutive years.